from flask  import Flask,g 

app = Flask(__name__)


@app.before_request
def bf():
    g.x = 666

@app.route('/n1')
def n1():
    print(g.x)
    return "n1"

@app.route('/n2')
def n2():
    print(g.x)
    return "n2"

if __name__ == "__main__":
    app.run()